Ferromagnetic &#34;n&#34; counter



Jan. 25, 1966 J. M. MOTIL FERROMAGNETIC "N" COUNTER Filed Sept. 24, 1962 //v VEN TOR JOHN M. Ma 7'/L B Y- KM A 7'7'0RNE rs United States Patent Ofiice 3,231,721 Patented Jan. 25, 1966 3,231,721 FERROMAGNETIC N COUNTER John M. Motil, flttawa, Ontario, Canada, assignor to Northern Electric Company Limited, Montreal, Quebec, Canada Filed Sept. 24, 1962, Ser. No. 225,522 Claims. (Cl. 23592) This invention relates to a counting device utilizing a ferromagnetic counting unit.

Many devices and circuit arrangements have in the past been developed for counting discrete events which are capable of being translated into electric signals or pulses. Many such arrangements comprise so-called flip flop or bistable circuits having only two stable conditions with the result that a high capacity counting arrangement involves many components and relatively high cost. This is so because, with a binary system of this type it is necessary, in order to be able to accommodate the counting of a large number of events, to have a correspondingly large number of flip-flop circuits connected, one after the other so as to provide the required counting capacity. Moreover, the data yielded by a counter of this type is necessarily in binary form and, if a decimal read-out is to be obtained, relatively complicated translation circuits are required. In some other, prior counter proposals various assumptions are made concerning the timing or duration of events to be counted and, while these are satisfactory in cases where the assumptions are satisfied under operating conditions, the arrangements in question are not satisfactory where the events to be counted are of extremely variable duration or are of random occurrence. In still other prior counter arrangements multi-winding relays are used, thus complicating the circuit and rendering the design relatively more expensive. Finally, so far as I am aware, most prior counter circuit arrangements must be designed for a fixed base n (such as multi-vibrators in which n can be 2 only), thus limiting their usefulness and flexibility.

It is accordingly an object of my invention to provide, within the limitations imposed by the speed of operation of relays, a counting device which, with a minimum of components including a relay having but one winding, is capable of counting a plurality of events 11, and in particular the useful facility 21:10 so as to give decimal data, and at the same itme providing a counter arrangement in which n can be simply varied and which is capable of recording events of random duration and fre quency.

I have found that an extremely useful counting device can be obtained, capable of counting a plurality of events 12:1 to n=n, by a circuit arrangement which includes a relay requiring but a single winding and at least one transfer contact, a resistor, a resistor-condenser series combination, a source of DC. potential, and a trigger adapted to be actuated upon the occurrence of each of the events. In accordance with my invention I arrange the winding of the relay to be connected through the resistor across the terminals of the source of potential so as to set up a holding current in the winding. I further provide circuit connections, which include the trigger and the relay contacts, whereby, prior to the occurrence of the first event n=1, the series combination is connected across the source so that the condenser becomes charged. Upon occurrence of the said first event n=1, the trigger is caused to move from its normal position so as to connect the series combination across the terminals of the winding, thus causing the relay to close as a result of the condenser discharging into the winding. At some time during or after the occurrence of the event n=l, and prior to the occurrence of the event n=2, the trigger returns to its normal condition whereby (due to the change in condition of the relay) the series combination is shorted so as to discharge the condenser, the series icombination is shorted so as to discharge the condenser, the relay in the meantime remaining in closed position due to the holding current. Thereafter, upon the occurrence of each of the events 11:2 to n=n the trigger again applies the discharged series combination across the terminals of the winding. By proper choice of the circuit components, it is possible so to arrange that, upon occurrence of the nth event, the action of the trigger in connecting the series combination across the winding of the relay causes the state of the magnetic circuit to be modified so that the relay opens and the counting cycle will commence again, upon the occurrence of the next event.

By the term holding current is meant a current which, while in itself not sufiicient to cause closing of the relay, will maintain the relay in closed position once it attains that state.

My invention will be described in detail in connection with the attached figure of drawings.

A relay generally represented at 1 has a winding 2 and a transfer contact generally represented at 3. The transfer contact in turn comprises a pole contact 4 and break and make contacts 5 and 6 as shown. The relay arrangement is such that, when the relay is released the pole 4 is connected to the break contact 5 whereas, when the relay is operated, the pole 4 is connected to the make contact 6. As shown in the drawing, the winding 2 of the relay is connected through resistor 10 to one terminal 11 of a direct current supply, the other end of the winding being connected to the other terminal 12 of the supply. The resistor 10 which for convenience may be variable is so selected as to ensure that there is set up in the winding 2 a holding current. The contacts 5 and 6 of the relay are respectively connected to the trminals 11 and 12, as shown. The circuit also includes a series resistor-condenser combination generally represented at 7 comprising a resistor 8 and a condenser 9, one terminal of which is connected to the point 12. A trigger, generally represented at 15 is for the purpose of convenience here illustrated as a single pole double throw switch having a pole contact 16 and two other contacts 17 and 18. The trigger 15 is adapted to be actuated upon the occurrence of the events to be counted. The normal condition of the trigger is such that the pole 16 isconnected to the contact 18i.e. the condition shown in the drawing. Upon occurrence of one of the events to be counted, the condition of the trigger is changed so that the pole 16 is connected to the contact 17. At some time during or after termination of the event the trigger returns to its normal condition. As will be apparent to persons skilled in the art there are many components and circuit arrangements which could be used to form a trigger having the required characteristics. As shown, the upper end of the resistor 8 is connected to the pole 16, whereas the contacts 17 and 18 are respectively connected to the junction between the winding 2 and the resistor 10 and the pole 4 of the relay 1.

Prior to the occurrence of the first event to be counted, the condition of the circuit is that shown in the drawingi.e. the condenser 9 is charged through the resistor 8 as a result of being connected across the terminals 11, 12 of the source of DC. potential. Upon the occurrence of the first event to be countedi.e. n'=l, the trigger 15 is actuated so as to cause the charged condenser 9 to be applied across the terminals of the winding 2 from the resistor 8. This momentarily increases the current flowing through the winding 2 so as to cause the relay to operatei.e. causing pole 4 to be connected to make contact 6, 'Upon release of the trigger 15 to its normal condition, the upper end of the resistor S is once again connected to the pole 4 of the relay 1. Now however the circuit is such that the series combination 7 is shorted, and the condenser 9 consequently discharges through the resistor 8, Upon the occurrence of the next event 11:2, the discharged condenser 9 is connected across the terminals of the winding 2, through the resistor 8' and this is repeated for each of: the subsequent events n=3 to 11:11. The successive application, across the terminals of the winding 2, of the discharged series combination (i.e. discharged condenser 9 in series with the resistor 8'), has what may conveniently be called a cumulative ferromagnetic effect. By appropriate selection of the circuit components it is possible so to design the arrangement that, upon the occurrence of the nth event to be counted, the application of the discharged series combination 7 across the terminals of the winding 2', causes the relay to release, this again connecting the pole 4 to the break contact 5, whereby the counting sequence can commence once more.

While I do not wish to be bound by any particular theory of operation of my invention, it would seem that the successive applications of the discharged condenser 9, in series with the resistor 8, across the winding 2 affects the state of the magnetic circuit of the relay in some consistently repeatable manner whereby satisfactory counting results can be obtained. The number n is apparently limited only by the number of practically distinguishable states within the ferromagnetic material. Even at relatively high values of n, the operation of my counter arrangement is, while not precisely accurate, sufficient to give useful results where only an approximate count is required.

In one specific embodiment of my invention, designed for 11:3, the relay used was a standard Bell Telephone unit designated by the symbol AF67. The source of DC. potential was 48 volts. The resistor 8 and condenser 9 were respectively 1300 ohms and 3 mid. The resistor 10 was a potentiometer adjusted to the proper holding current conditions which in this case was about 9000 ohms. I

What I claim as my invention is:

1. A counting device adapted to be actuated by a trigger means comprising a relay having a winding and a transfer contact, a resistor, a resistor-condenser series combination, and a trigger adapted to be actuated upon occurrence of each of the events, said winding and said resistor being connected in series across a source of DC. potential adapted to establish a holding current in said winding; connection means, including said trigger, for connecting said series combination across said winding upon the occurrence of each of the events to be counted, and further connection means including said trigger means and said transfer contact for charging said condenser prior to the said first event, and thereafter discharging said condenser following return of the trigger to normal position after actuation thereof by each successive event.

2. A device for counting the events n=l to 11:12 wherein n is greater than 2 comprising a relay having a winding and a transfer contact; a resistor, a resistor-condenser series combination, and a trigger means adapted to be actuated upon the occurrence of said events; said resistor and winding being connected across -a source of DC. potential adapted to establish a holding current in said winding; connection means whereby, when the relay is released, the series combination is connected across a source of 'D.C. potential so as to charge the condenser thereof, and when the relay is operated the series combination is shorted so as to discharge the condenser; and further connection means including said trigger whereby the series combination is connected across said winding upon the occurrence of each of the saidevents.

3. A device for counting events rv=1 to n=n where n is greater than 2, comprising a relay having a Winding and a transfer contact; a resistor, a resistor-condenser series combination, and a trigger adapted to be actuated upon. the occurrence of each of the events; said resistor and Winding being connected in series with a source of DC. potential whereby a holding current is established in the winding; connection means, including said contact and said trigger, whereby (a) prior to the occurrence of the first event n=1 the said series combination is connected to a source of DC. potential so as to charge the condenser (b) upon the occurrence of each of the eventsn: 1 to n=(1) the said series combination is connected across the winding and is thereafter disconnected from the winding and shorted and (0) upon occurrence of the event n=n the said series combination is again connected across the winding whereby the relay is released.

4. A device for counting events 11:1 to 21:11 wherein n is greater than 2 comprising a relay having a winding and a transfer contact; a resistor; a resistoracondenser series combination; a trigger adapted to be actuated upon occurrence of each of theeve'nts; and a source of DC. potential; one end of the winding being connected to one terminal of the said source, the other end being connected through said resistor to the other terminal of said source whereby a holding current is established in the winding; a connection between one end of said series combination and said one terminal of said source; connection means, including said trigger means, whereby the other end of said series combination is normally connected to the transfer contact and is, upon the occurrence of each of said events connected to the other end of said winding; means connecting the transfer contact to the terminals of said source whereby, when the trigger is in normal condition, the condenser is charged by said source, when the relay is released, and the series combination is shorted when the relay is operated.

5. A device for counting 11 events wherein n is greater than 2', comprising; a relay having a winding and pole, break and make contacts; a resistor; a resistor-condenser series combination; a trigger adapted to be actuated upon the occurrence of each of the events, and thereafter return to a normal position; and a source of DC. potential; means connecting one end of the winding, one end of the series combination and the make contact to one terminal of the source; means connecting the other end of the References Cited by the Examiner UNITED STATES PATENTS 2/1958 Pittman et al 235-92 OTHER REFERENCES Pages 3-5, December 1951, Multi-Stable Magnetic Memory Techniques by Good'el'l and Lode, Radio-Electronics Engineering.

MALCOLM A. MORRISON, Primary Examiner. 

1. A COUNTING DEVICE ADAPTED TO BE ACTUATED BY A TRIGGER MEANS COMPRISING A RELAY HAVING A WINDING AND A TRANSFER CONTACT, A RESISTOR, A RESISTOR-CONDENSER SERIES COMBINATION, AND A TRIGGER ADAPTED TO BE ACTUATED UPON OCCURRENCE OF EACH OF THE EVENTS, SAID WINDING AND SAID RESISTOR BEING CONNECTED IN SERIES ACROSS A SOURCE OF D.C. POTENTIAL ADAPTED TO ESTABLISH A HOLDING CURRENT IN SAID WINDING; CONNECTION MEANS, INCLUDING SAID TRIGGER, FOR CONNECTING SAID SERIES COMBINATION ACROSS SAID WINDING UPON THE OC- 